Anyone who’s had a root canal infection will testify that they’re unpleasant experiences, but most of us wouldn’t think beyond the immediate discomfort. However, Dr Sadia Niazi’s recent work has shown that treatment of root canal infections can improve our general health.

Dr Niazi is an endodontic specialist, meaning that she is an expert in understanding and treating the dental pulp – the connective tissue in the inner tooth that is affected by root canal infection. Previous research had shown that the bacteria found in gum infections can affect systemic inflammation, but no one had investigated whether root canal infections, which have even easier access to the bloodstream, could have a similar effect.

“I found it fascinating that there was lots of research at the time showing that periodontal (gum) disease can impact the general health of patients,” Dr Niazi explained. “However, when I started exploring the same connections between endodontic (root canal) infections, I couldn’t find strong evidence. This was surprising, since root canal infections are regarded as the third most prevalent oral disease globally.”

Dr Niazi’s path to her dental career began in Pakistan, where she completed her training at the biggest dental hospital (Armed Forces Institute of Dentistry) in the country. She then moved to the UK to complete a Master’s in Experimental Oral Sciences/Pathology at the Queen Mary University of London. “That was my first real exposure to working in research labs,” Dr Niazi said. “The experience sparked my interest in combining clinical practice with the research.”

Dr Niazi went on to complete her PhD in Endodontics Microbiology here at King’s, under the supervision of Professors David Beighton and Francesco Mannocci. She acknowledges Dr. Douglas Clark, who trained her in microbiology techniques: “He equipped me with all the basics of microbiology. I'm still teaching those techniques to my students today.” During this time, Dr Niazi also completed her General Dental Council (GDC) exams, which qualified her to practice in the UK and fulfil the clinical aspects of her PhD. In 2017, she became Fellow of the Higher Education Academy. Her early research found that hospital-acquired bacteria were present in the infected root canals and identified unchanged operators’ gloves as a possible source of cross contamination. This hypothesis led to a clinical trial which showed that adhering to a good cross infection protocol increases the success of root canal treatment.

Dr Niazi was selected as an Academic Clinic Fellow in 2018 and completed her specialist training in Endodontic from King’s College London in 2020. She became a Clinical Lecturer and Honorary Consultant at King’s in 2021, and member of The Royal College of Surgeons of Edinburgh, and Royal College of Surgeons of England. Since completing her PhD, Dr Niazi has focused on the connection between root canal infections and general health. Her most recent work has shown that successful treatment and healing of root canal infections reduces inflammation in the rest of the body. This landmark study attracted global media attention, making headlines over 800 media outlets, including The Guardian, The Telegraph, The Washington Post, Fox News, Everyday Health, and ConSalud.es.

“The story sends a great positive message that root canal treatment isn’t just about relieving pain or saving teeth – it’s about improving overall health, particularly reducing the risk of chronic conditions like heart disease and diabetes,” Dr Niazi said. “Most importantly, it raises the profile of King’s and the innovative research that we are doing here. When I started this work, I faced a lot of challenges about the lack of prior evidence linking root canal infection with general health. Despite that, I had a very strong belief – backed by my research experience – that the biological pathways triggered by gum infections and root canal infections would be fundamentally similar. That conviction is what drove me to pursue this research.”

The connection between oral health and general health is topical, especially at a time when access to NHS dentists can be challenging. “Dentistry and Medicine have been seen as two different fields, with oral health being kept separate from the general health,” Dr Niazi said. “We need to move towards more integrated care, where dentists and physicians work together to identify patient risk, coordinate management and protect long term patient well-being. We need to get patients’ oral health to a good standard, particularly for high-risk patients such as ones who are diagnosed with diabetes, cancer, or cardiac problems. Following diagnosis, these patients should receive timely referral to the dentist to optimise their oral health and reduce the related general health risks. Currently, we often receive referrals at the very last minute - just before patient is starting the chemotherapy or undergoing major cardiothoracic procedures. By that stage, it’s simply too late.”

Dr Niazi became a Senior Clinical Lecturer at King’s in 2024, and she is adjunct faculty in her alma mater in Pakistan. She is also Fellow of The Royal College of Surgeons of Edinburgh, and council member of the British Endodontic Society. She has received various awards including her faculty’s Students Support Award, the Collaborative Research Award, and the Inspirational Full-time Lecturer award by the British Endodontic Society. Looking ahead, Dr Niazi is now extending her research to patients who have metabolic syndromes, and she hopes to explore different geographic populations. For example, there is a high prevalence of cardiometabolic disorders in Southeast Asia, and there is no equal access to dental care. She is a strong advocate of integration of root canal infection prevention and treatment into global health strategies, and her goal is recognition of these infections within the non-communicable disease in the WHO’s Global Oral Health Action Plan. She is actively pursuing her goals and raising awareness through delivering lectures at national and international conferences, holding symposia and engaging is patient & public involvement activities.